Impact of an education intervention using email for the prevention of weight gain among adult workers

Abstract

Objective: To evaluate the impact of a worksite intervention to prevent weight gain among adult workers.

Design: A controlled community trial was performed by dividing the workers into two groups: intervention group (IG) and control group (CG). The theoretical framework applied was Intervention Mapping Protocol and the intervention was implemented through interactive software for weight self-monitoring. To evaluate the impact of the intervention, the differences in weight, BMI and waist circumference between the IG and CG were assessed before and 6 months after the intervention by regression models. Additionally, the sustainability of the intervention was evaluated at 12 months after the intervention. Settings São Paulo, Brazil.

Subjects: Four companies; 281 workers for the analysis of effectiveness and 427 for the analysis of sustainability.

Results: The intervention resulted in significant reductions in weight, BMI and waist circumference in the IG compared with the CG. The impact of the intervention on IG individuals' body weight was -0·73 kg, while the weight of CG individuals increased. IG individuals with adequate initial weights did not show significant variations, while those who were overweight demonstrated a significant reduction in body weight. The intervention resulted in a reduction of 0·26 kg/m2 in BMI and 0·99 cm in waist circumference, and the sustainability analysis after 12 months showed a continued reduction in body weight (-0·72 kg).

Conclusions: The behavioural intervention was effective, resulting in weight maintenance among participants with adequate initial weight and in significant reductions among those who were overweight. More research on longer-term weight maintenance is needed.

Fig. 1

Trial profile of participants; Healthy Weight Program, São Paulo, Brazil, 2008

Fig. 2

Mean change in (a) self-reported weight and (b) BMI in the analysis of effectiveness at 6 months (n 281) according to allocation group (IG, intervention group; CG, control group) and initial presence of overweight (, normal weight, BMI < 25·0 kg/m²; , overweight, BMI ≥ 25·0 kg/m²); Healthy Weight Program, São Paulo, Brazil, 2008. Values are means with their 95 % confidence intervals represented by vertical bars; *mean change (6 months v. 0 months) was significant (P < 0·05)